The present invention generally relates to a display arrangement, and more particularly, to an image display system which is capable of displaying image information written on a sheet of paper or the like, on a display board, and also, capable of printing the image information displayed on the display board onto a sheet of paper, etc.
Recently, there has been proposed a so-called electronic blackboard capable of copying an image written on a board, so as to replace a conventional blackboard. The electronic blackboard referred to above is so arranged as to read the image hand-written on a white board or the like, for example, with a felt tipped pen, by an image reading device and for printing the read information through a printing unit. This electronic blackboard is convenient to use, since an operator is not required to manually copy the image written on the board into a notebook, etc.
Meanwhile, as a means for simultaneously transmitting information of data preliminarily prepared to a large number of listeners, there has been proposed an apparatus called an overhead projector (referred to as an OHP hereinafter), which is arranged to enlarge and project by light, the information printed or written on a transparent sheet, and is also convenient to use, since it becomes possible to explain the data by use of a pointing rod, without the necessity for preliminarily distributing data to the audience.
Moreover, there has also been conventionally proposed, for example, in Japanese patent publication (Tokkosho) No. 57-27463, a magnetic migration display board which is arranged to display data through utilization of magnetic migration.
However, the conventional arrangements as referred to above respectively have various disadvantages as follows.
In the electronic blackboard, for example, in order to transmit the preliminarily prepared data to many people, it is necessary to manually transcribe the data onto the electronic blackboard or to preliminarily copy the data for distribution to the audience.
The OHP also has problems in that the projected image can not be copied for distribution, original documents formed by transparent sheets are required, and it is necessary to darken the room for the projection by light.
Furthermore, the magnetic migration display system has a problem such that when the information displayed on the display unit is required to be rewritten, much time is taken because a new information can only be displayed after once completely erasing the information on the display unit by an erasing head.